Activation-induced cytidine deaminase is dispensable for virus-mediated liver and skin tumor development in mouse models

Tung Nguyen, Jianliang Xu, Shunsuke Chikuma, Hiroshi Hiai, Kazuo Kinoshita, Kyoji Moriya, Kazuhiko Koike, Gian Paolo Marcuzzi, Herbert Pfister, Tasuku Honjo, Maki Kobayashi

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2 Citations (Scopus)

Abstract

Activation-induced cytidine deaminase (AID) not only promotes immune diversity by initiating somatic hypermutation and class switch recombination in immunoglobulin genes but also provokes genomic instability by introducing translocations and mutations into non-immunoglobulin genes. To test whether AID is essential for virus-induced tumor development, we used two transgenic tumor models: mice expressing hepatitis C virus (HCV) core proteins (HCV-Tg), driven by the hepatitis B virus promoter, and mice expressing human papillomavirus type 8 proteins (HPV8-Tg), driven by the Keratin 14 promoter. Both strains were analyzed in the absence and presence of AID by crossing each with AID-/- mice. There was no difference in the liver tumor frequency between the HCV-Tg/AID+/+ and HCV-Tg/AID-/- mice at 20 months of age although the AID+/+ mice showed more severe histological findings and increased cytokine expression. Furthermore, a low level of AID transcript was detected in the HCV-Tg/AID+/+ liver tissue that was not derived from hepatocytes themselves but from intra-hepatic immune cells. Although AID may not be the direct cause of HCVinduced oncogenesis, AID expressed in B cells, not in hepatocytes, may prolong steatosis and cause increased lymphocyte infiltration into HCV core protein-induced liver lesions. Similarly, there was no difference in the time course of skin tumor development between the HPV8-Tg/AID-/- and HPV8-Tg/AID+/+ groups. In conclusion, AID does not appear to be required for tumor development in the two virus-induced tumor mouse models tested although AID expressed in infiltrating B cells may promote inflammatory reactions in HCV core protein-induced liver pathogenesis.

Original languageEnglish
Article numberdxu040
Pages (from-to)397-406
Number of pages10
JournalInternational immunology
Volume26
Issue number7
DOIs
Publication statusPublished - 2014 Jul
Externally publishedYes

Keywords

  • Hepatitis C virus
  • Human papillomavirus type 8

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology

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  • Cite this

    Nguyen, T., Xu, J., Chikuma, S., Hiai, H., Kinoshita, K., Moriya, K., Koike, K., Marcuzzi, G. P., Pfister, H., Honjo, T., & Kobayashi, M. (2014). Activation-induced cytidine deaminase is dispensable for virus-mediated liver and skin tumor development in mouse models. International immunology, 26(7), 397-406. [dxu040]. https://doi.org/10.1093/intimm/dxu040